I have a Mazda CX5 that runs a built in dash TOMTOM NB1 Navigation system. I am running a patched version of the latest navcore 10.854. The NB1 supports TMC traffic, however in Australia, the signal is encrypted so only devices/car manufacturers that have purchased a license with SUNA can decrypt and use the traffic data. (this is not something where the end user can purchase a subscription. The manufacturer must purchase a license in order to incorporate the necessary decryption key into their software.

http://www.intelematics.com/wp-content/uploads/Click-here-for-Suna-RDS-TMC-Product-Description.pdf

Intelematics Australia[30] broadcasts a national encrypted RDS-TMC service focused initially on urban Australia under the brand 'SUNA Traffic Channel'. The service reaches around 85% of urban Australia, using commercial FM broadcasters in seven cities, as well as via XML for online and smartphone applications. The service is available on GPS navigation systems including Navman, Mio, Uniden, iPhone (Navigon & Sygic), Eclipse, Pioneer, Alpine and Clarion. SUNA Traffic Channel is also available in Ford, Holden, Toyota, Nissan, and Mercedes Benz navigation systems. SUNA is currently the only source of comprehensive, metropolitan congestion monitoring content in Australia – proprietary technology interfaces to traffic light control systems. The SUNA broadcast service is fully compliant with both RDS and TMC. However, since the broadcast is encrypted it does not work on in-car GPS navigation systems that do not have a commercial arrangement with SUNA.

I discovered that while no current model tomtoms support SUNA TMC in Australia, a number of older devices did.
http://www.sunatraffic.com.au/suna-compatible-devices/suna-compatible-devices-older-models/
Those devices are:
XXL 540, XL 340, One 140, 730 Traffic, XL Traffic and Go 720 Traffic

Many things have pointed me towards the mctx.dat file containing valid tmc decryption keys.

My idea is to take the mctx.dat file from an older navcore from one of the older SUNA supported devices above (which should include decryption key), and replace the mctx.dat on the current 10.854 navcore (which does not include the decryption key).

This task becomes a little more complicated, as a mctx.dat file does not reside on the root of a MAZDA SDCARD. It does however reside within the ttsystem file of navcore 10.854.

Someone was able to extract the files from within the ttsystem file for me using LINUX and I found the mctx.dat file within those extracted files.

I run a mac, but i have just installed linux using parallels virtual machine. I have no experience using linux, but need to work out how to:

1) Extract the files from within the 'patched' 10.854 mazda nb1 navcore
2) Replace the mctx.dat with the one from http://download.tomtom.com/sweet/navcore/8.351.go530-go730-go930.CAB-navcore-GO.cab
3) Re-archive the files into a valid ttsystem file
4) Copy the ttsystem file to my sdcard root to install on the MAZDA
5) Hopefully enjoy TMC traffic!

Any thoughts, advise and help greatly appreciated!

Thanks.